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<hr>
<a name="Relocations-3"></a>
<h4 class="subsubsection">9.42.3.4 Relocations</h4>
<a name="index-Sparc-relocations"></a>
<a name="index-relocations_002c-Sparc"></a>

<p>ELF relocations are available as defined in the 32-bit and 64-bit
Sparc ELF specifications.
</p>
<p><code>R_SPARC_HI22</code> is obtained using &lsquo;<samp>%hi</samp>&rsquo; and <code>R_SPARC_LO10</code>
is obtained using &lsquo;<samp>%lo</samp>&rsquo;.  Likewise <code>R_SPARC_HIX22</code> is
obtained from &lsquo;<samp>%hix</samp>&rsquo; and <code>R_SPARC_LOX10</code> is obtained
using &lsquo;<samp>%lox</samp>&rsquo;.  For example:
</p>
<div class="example">
<pre class="example">sethi %hi(symbol), %g1
or    %g1, %lo(symbol), %g1

sethi %hix(symbol), %g1
xor   %g1, %lox(symbol), %g1
</pre></div>

<p>These &ldquo;high&rdquo; mnemonics extract bits 31:10 of their operand,
and the &ldquo;low&rdquo; mnemonics extract bits 9:0 of their operand.
</p>
<p>V9 code model relocations can be requested as follows:
</p>
<ul>
<li> <code>R_SPARC_HH22</code> is requested using &lsquo;<samp>%hh</samp>&rsquo;.  It can
also be generated using &lsquo;<samp>%uhi</samp>&rsquo;.
</li><li> <code>R_SPARC_HM10</code> is requested using &lsquo;<samp>%hm</samp>&rsquo;.  It can
also be generated using &lsquo;<samp>%ulo</samp>&rsquo;.
</li><li> <code>R_SPARC_LM22</code> is requested using &lsquo;<samp>%lm</samp>&rsquo;.

</li><li> <code>R_SPARC_H44</code> is requested using &lsquo;<samp>%h44</samp>&rsquo;.
</li><li> <code>R_SPARC_M44</code> is requested using &lsquo;<samp>%m44</samp>&rsquo;.
</li><li> <code>R_SPARC_L44</code> is requested using &lsquo;<samp>%l44</samp>&rsquo; or &lsquo;<samp>%l34</samp>&rsquo;.
</li><li> <code>R_SPARC_H34</code> is requested using &lsquo;<samp>%h34</samp>&rsquo;.
</li></ul>

<p>The &lsquo;<samp>%l34</samp>&rsquo; generates a <code>R_SPARC_L44</code> relocation because it
calculates the necessary value, and therefore no explicit
<code>R_SPARC_L34</code> relocation needed to be created for this purpose.
</p>
<p>The &lsquo;<samp>%h34</samp>&rsquo; and &lsquo;<samp>%l34</samp>&rsquo; relocations are used for the abs34 code
model.  Here is an example abs34 address generation sequence:
</p>
<div class="example">
<pre class="example">sethi %h34(symbol), %g1
sllx  %g1, 2, %g1
or    %g1, %l34(symbol), %g1
</pre></div>

<p>The PC relative relocation <code>R_SPARC_PC22</code> can be obtained by
enclosing an operand inside of &lsquo;<samp>%pc22</samp>&rsquo;.  Likewise, the
<code>R_SPARC_PC10</code> relocation can be obtained using &lsquo;<samp>%pc10</samp>&rsquo;.
These are mostly used when assembling PIC code.  For example, the
standard PIC sequence on Sparc to get the base of the global offset
table, PC relative, into a register, can be performed as:
</p>
<div class="example">
<pre class="example">sethi %pc22(_GLOBAL_OFFSET_TABLE_-4), %l7
add   %l7, %pc10(_GLOBAL_OFFSET_TABLE_+4), %l7
</pre></div>

<p>Several relocations exist to allow the link editor to potentially
optimize GOT data references.  The <code>R_SPARC_GOTDATA_OP_HIX22</code>
relocation can obtained by enclosing an operand inside of
&lsquo;<samp>%gdop_hix22</samp>&rsquo;.  The <code>R_SPARC_GOTDATA_OP_LOX10</code>
relocation can obtained by enclosing an operand inside of
&lsquo;<samp>%gdop_lox10</samp>&rsquo;.  Likewise, <code>R_SPARC_GOTDATA_OP</code> can be
obtained by enclosing an operand inside of &lsquo;<samp>%gdop</samp>&rsquo;.
For example, assuming the GOT base is in register <code>%l7</code>:
</p>
<div class="example">
<pre class="example">sethi %gdop_hix22(symbol), %l1
xor   %l1, %gdop_lox10(symbol), %l1
ld    [%l7 + %l1], %l2, %gdop(symbol)
</pre></div>

<p>There are many relocations that can be requested for access to
thread local storage variables.  All of the Sparc TLS mnemonics
are supported:
</p>
<ul>
<li> <code>R_SPARC_TLS_GD_HI22</code> is requested using &lsquo;<samp>%tgd_hi22</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_GD_LO10</code> is requested using &lsquo;<samp>%tgd_lo10</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_GD_ADD</code> is requested using &lsquo;<samp>%tgd_add</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_GD_CALL</code> is requested using &lsquo;<samp>%tgd_call</samp>&rsquo;.

</li><li> <code>R_SPARC_TLS_LDM_HI22</code> is requested using &lsquo;<samp>%tldm_hi22</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LDM_LO10</code> is requested using &lsquo;<samp>%tldm_lo10</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LDM_ADD</code> is requested using &lsquo;<samp>%tldm_add</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LDM_CALL</code> is requested using &lsquo;<samp>%tldm_call</samp>&rsquo;.

</li><li> <code>R_SPARC_TLS_LDO_HIX22</code> is requested using &lsquo;<samp>%tldo_hix22</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LDO_LOX10</code> is requested using &lsquo;<samp>%tldo_lox10</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LDO_ADD</code> is requested using &lsquo;<samp>%tldo_add</samp>&rsquo;.

</li><li> <code>R_SPARC_TLS_IE_HI22</code> is requested using &lsquo;<samp>%tie_hi22</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_IE_LO10</code> is requested using &lsquo;<samp>%tie_lo10</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_IE_LD</code> is requested using &lsquo;<samp>%tie_ld</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_IE_LDX</code> is requested using &lsquo;<samp>%tie_ldx</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_IE_ADD</code> is requested using &lsquo;<samp>%tie_add</samp>&rsquo;.

</li><li> <code>R_SPARC_TLS_LE_HIX22</code> is requested using &lsquo;<samp>%tle_hix22</samp>&rsquo;.
</li><li> <code>R_SPARC_TLS_LE_LOX10</code> is requested using &lsquo;<samp>%tle_lox10</samp>&rsquo;.
</li></ul>

<p>Here are some example TLS model sequences.
</p>
<p>First, General Dynamic:
</p>
<div class="example">
<pre class="example">sethi  %tgd_hi22(symbol), %l1
add    %l1, %tgd_lo10(symbol), %l1
add    %l7, %l1, %o0, %tgd_add(symbol)
call   __tls_get_addr, %tgd_call(symbol)
nop
</pre></div>

<p>Local Dynamic:
</p>
<div class="example">
<pre class="example">sethi  %tldm_hi22(symbol), %l1
add    %l1, %tldm_lo10(symbol), %l1
add    %l7, %l1, %o0, %tldm_add(symbol)
call   __tls_get_addr, %tldm_call(symbol)
nop

sethi  %tldo_hix22(symbol), %l1
xor    %l1, %tldo_lox10(symbol), %l1
add    %o0, %l1, %l1, %tldo_add(symbol)
</pre></div>

<p>Initial Exec:
</p>
<div class="example">
<pre class="example">sethi  %tie_hi22(symbol), %l1
add    %l1, %tie_lo10(symbol), %l1
ld     [%l7 + %l1], %o0, %tie_ld(symbol)
add    %g7, %o0, %o0, %tie_add(symbol)

sethi  %tie_hi22(symbol), %l1
add    %l1, %tie_lo10(symbol), %l1
ldx    [%l7 + %l1], %o0, %tie_ldx(symbol)
add    %g7, %o0, %o0, %tie_add(symbol)
</pre></div>

<p>And finally, Local Exec:
</p>
<div class="example">
<pre class="example">sethi  %tle_hix22(symbol), %l1
add    %l1, %tle_lox10(symbol), %l1
add    %g7, %l1, %l1
</pre></div>

<p>When assembling for 64-bit, and a secondary constant addend is
specified in an address expression that would normally generate
an <code>R_SPARC_LO10</code> relocation, the assembler will emit an
<code>R_SPARC_OLO10</code> instead.
</p>
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